Questions from a new reloader...

[The Annoyed Man]

I took forever to set up all the gear I bought 6 months ago, but my son and I finally started rolling our own a week ago. Anyway, we started with .308 Winchester, and I had very good results with the low end load recommendation for 168 grain SMKs. I have a question regarding cartridge overall length.

I did up three loads last night taken from the Lyman manual (I believe it is the most recent edition). The bullet is a 175 grain SMK, using Varget powder, in new Remington brass with Winchester Large Rifle primers.

The first load is the low end at 40 grains of powder. The second load splits the difference between the low and high recommended loads at 42.6 grains. The third load is the hot load of 45.2 grains of Varget.

The Lyman manual says that COL should be 2.800". The problem is that my 175 grain SMKs are turning out not to be of consistent length. I seated a bullet by slowing adjusting the die down down (RCBS die in a Rockchucker press) to the point where I had an OAL of exactly 2.800", and then carefully tightened the lock nut. I checked it again by seating a second bullet, and got an OAL of about 2.7995" and called it good. But the next one came out to 2.795". And then I got another one at 2.805". The die is well tightened in the turret, and I am pulling the lever down to the stops each time; so I am pretty certain that it has nothing to do with how I am using the press. I loaded up a bunch of 168 grain SMKs at different powder levels, using the same press and die, and the variations in OAL were no more than .001" in either direction — too small to be of a concern to me at this point.

I guess my question is, will .005" one way or the other actually make that much difference? The reason I am concerned is that the third load, at 45.2 grains of powder, is a compressed load.

Has anyone else experienced differences in bullet length with the 175 grain SMKs?

FWIW, the rifle is a Remington 700 VSF with a 26" heavy fluted barrel. It is in stock trim, with original barrel and action. I don't really know what the distance to the lands is, so I don't know if a OAL that is .005" too long will engage the lands on loading and more deeply seat the bullet when closing up and locking the bolt.

Lastly, the test barrel for the Lyman book is 24", but my Remington's barrel is 26". Is the extra 2" in my barrel length likely to have any effect one way or the other on pressures?

Any suggestions? Or am I worrying too much about it? Thanks in advance for any help you can offer me.

 

[Tilos]

Welcome the world of reloading science.

As you are new to reloading, I would suggest you not start loading anything close to the top of the range for the powder you are using.

As for OAL, at the range, you can chamber a round and feel how the bolt closes.
Without firing, you can remove that round and look for rifling contact marks on the bullet and measure the OAL and compare it to the "before chambered" measurement for any set back.

If this does not answer your concerns, don't shoot the reloads and buy a bullet puller on your way home from the range.

Most rifles have a lot of free bore before the rifling.

Tilos

 

[The Annoyed Man]

Thanks for the reply.

I actually did start with the low end of the range on the 168s and checked for overpressure signs before loading up some medium and hotter loads, which I haven't shot yet. But I won't shoot the hotter 168 load until I'm satisfied that the medium load shows no signs of overpressure either. And I'm not going to shoot any of the 175 grain SMKs until I'm done testing the 168s.

 

[ants]

1. Most of us work up a load a few TENTHS at a time. Not low-medium-max. You will find your accuracy load easier if you work up slowly.

2. With good equipment like you have (and a good bullet like you have) an OAL variation of 0.010 inch from one to the next is just fine for a beginner. You seem to be within that range. Later, when you load super match ammo for your super match rifle at 600 yard matches, it will be more important to be precise.

 

[W.E.G.]

You need a tool that allows you to measure from the base of the cartridge to the ogive of the bullet.

Measuring COL with Sierra Matchkings is an exercise in futility unless you buy a tool to uniform the distance from the ogive to the tip.

Get one of these:
http://www.midwayusa.com/viewproduct/?productnumber=574297


My usual rant:

You cannot use the RCBS tool to measure your chamber.

Yes, it does come with that bullet-looking-thing.
Supposedly you can use the bullet-looking-thing to measure base to ogive.

Provided that all your bullets are shaped just like the bullet-looking-thing.

The bullet-looking-thing is a complete PIECE OF ****.
If you buy the RCBS Precision Mic, throw the bullet-looking-thing away immediately.

The micrometer parts are excellent, and well worth the investment.



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You measure your CHAMBER with headspace gages.
Never anything else.
Always use headspace gages.



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You can use the Hornady (formerly Stoney Point) tools to measure base to ogive for whatever particular bullet you are loading.









NEVER measured fired cases from a gas-operated center-fire rifle, and expect to have even a remotely close, or consistent, measurement of the chamber.

Fired cases from a a gas-operated center-fire rifle will always measure MUCH LARGER than the actual chamber. Furthermore, the cases will be inconsistent sizes.

The firing-and-ejection process stretches the "headspace" dimension of cases fired in a gas-operated center-fire rifle.

 

[rfwobbly]

Mr Man -
Your variability is probably coming from 1 or 2 places...

• Most rifle dies do not push on the exact tip end of the bullet. Take your die apart and look at the mechanism, please. They usually have a small cup that fits over the bullet point and pushes on the "ogive". As the curve of the ogive changes from bullet to bullet, then the resulting OAL will also vary as a mathematical function of the ogive's curve formula.

• If your dies DO push on the tip of the bullet, then differences in seating force could collapse any soft nose bullet different amounts, resulting in OAL variations.

• Regardless of your die design, you always want to use slow steady strokes for all your reloading press movements. If you're feeling huge resistance during one portion of the stroke on any stage, then lube the brass, lube the machine, or prep (de-burr) the brass better. You should be able to use smooth steady strokes on all phases of reloading.

 

[JimKirk]

I suggest using one these Sinclair Hex Nuts with your calipers, there are two sizes that will fit many bullets.

http://www.sinclairintl.com/prod_detail_list/s


Jimmy K

 

[James2]

Any suggestions? Or am I worrying too much about it?

I would not worry about that little variation in OAL. It is not important.

I would worry about jumping to that high load. Like has been said, we usually work up a few tenths at a time. I have never found it desirable to use the max load. Most generally I find a sweet spot below maximum where the load exhibits good to excellent accuracy. That is really what I am after; hitting the target. I could care less about another 100 FPS.

 

[Tilos]

The Annoyed Man: thanks for the acknowledgement.

I often post in threads where the OP does NOT have the curtesy to thank those who attempt to help.
Many threads go off in tangents/debates about nothing relavent to the original question.
In that case I see no need the thank anyone.

Tilos

 

[918v]

A .010" OAL variance is normal with mass produced bullets. If you want a more consistent OAL, buy custom benchrest bullets. They are made one at a time on a single die. Your variance is gonna be in the .002" range.

 

[The Annoyed Man]

Thank you everyone for your replies so far.

To W.E.G., I will take your tool recommendations under advisement and start purchasing them as I can afford to.

To rfwobbly, I'm pretty sure the seating die pushes on the ogive of the bullet, as it sometimes leaves a faintly discernible "ring" mark around the bullet where the pressure was applied. This is not a permanent mark. I am using slow, steady strokes to seat the bullets.

To JimKirk, that link didn't work for me. What is the purpose of that hex nut and how does it work?

To Tilos, you are certainly welcome. I need all the help I can get. BTW, I bought a bullet puller with all my other gear, because I knew in advance I would do something boneheaded and want to take the bullet out.

To all, I will pull the bullets on the hot loads and start again in increments of .2 grains of powder. I guess I was being impatient by loading low/medium/hot loads.

As far as accuracy goes, I've already fired two groups of 4 hand loads each last Sunday (a week ago), using the low end load with the 168 grain SMKs over 41 grains of Varget in my Remington 700. With this rifle, I typically get groups in the .5"-1.0" range at 100 yards, using Black Hills Match or Federal Match. The variations are due more to my own limitations as a shooter than anything else, I think. With the hand load however, I got a first group of .5" in a clover leaf shape. The second group was four rounds into two holes measuring .375" center to center. I am not a brilliant shot, so I attribute the performance improvement to the ammo.

Thanks again to one and all.

 

[Damon555]

In my opinion 1/10th of a grain is too small an increment to start loading. I understand about wanting to tune a load perfectly and that should be done once you've eliminated the ones that cause pressure problems....but I work in .5 grain increments. Again, just my opinion formed by 12 years of reloading. (a very short time compared to most of the fine gentleman here)

 

[qajaq59]

To all, I will pull the bullets on the hot loads and start again in increments of .2 grains of powder. I guess I was being impatient by loading low/medium/hot loads.

Good move. And you will likely find your most accurate load somewhere between mid and max. Rarely do I have the best load at max. In fact I think it has only happened once.